Invoice refers to the text issued by the seller to the buyer in economic activities, including the name, quality and agreed price of the products or services provided to the buyer. In addition to the advance payment, the invoice must include the payment from the buyer to the seller according to the agreed conditions, and must include the date and quantity, which is an important proof of accounting. China's accounting system stipulates that valid invoices for purchasing products or services are called tax invoices. The vouchers of government departments' fees and levies have different names in different periods and different fees and levies, but most of them are collectively referred to as administrative fees and receipts. For internal audit and audit, each invoice must have a unique journal number to prevent